This is mostly a problem within avocado as serial generally isn't busy enough to overfill pipes. However the consequences of recording a failed write will haunt us on replay when the log will be out of sync to the playback.
Fixes: https://gitlab.com/qemu-project/qemu/-/issues/2010 Message-Id: <[email protected]> Acked-by: Pavel Dovgalyuk <[email protected]> Reviewed-by: Philippe Mathieu-Daudé <[email protected]> Signed-off-by: Alex Bennée <[email protected]> --- v2 - add explicit if REPLAY_MODE_RECORD leg with comment. --- chardev/char.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/chardev/char.c b/chardev/char.c index 996a024c7a..48f28881c2 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -171,6 +171,18 @@ int qemu_chr_write(Chardev *s, const uint8_t *buf, int len, bool write_all) return res; } + if (replay_mode == REPLAY_MODE_RECORD) { + /* + * When recording we don't want temporary conditions to + * perturb the result. By ensuring we write everything we can + * while recording we avoid playback being out of sync if it + * doesn't encounter the same temporary conditions (usually + * triggered by external programs not reading the chardev fast + * enough and pipes filling up). + */ + write_all = true; + } + res = qemu_chr_write_buffer(s, buf, len, &offset, write_all); if (qemu_chr_replay(s) && replay_mode == REPLAY_MODE_RECORD) { -- 2.39.2
